VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1940 Chevy Business Coupe help

Hello everyone. This is my first time posting tl this forum. I just bought a 1940 Chevy Business Coupe from the son of the man who restored it about 20 years ago but passed away. Its in great shape however I ran into some issues since its been delivered to me. When I took it out for its first weekend I noticed a slight drip coming from the front of the engine. I thought this might be coolant which accumulated from the overflow. I checked the coolant the morning after my cruise and it was nearly empty. I topped off my radiator and drove it back to my storage unit. The next weekend I drained the coolant and noticed it was a dirty brown. Either I have rust in my water jacket or the previous owner used Dexcool (that horrible orange stuff). Anyhow I flushed the system, topped it off, and started my journey. About an hour into my drive my temp gauge shot up to 212 so I stopped to check it out. Coolant was pouring from by the water pump. Since I was 15 miles from home I topped up and "hopped" the car home. The temp gauge stayed warm...around 180 but as soon as it jumped to 212 I'd stop and check the fluid. I was able to get home about an hour later. The next morning the radiator was empty. When I topped it up it just leaked out of the bottom of the water pump. I called Hagerty and used my policy to flatbed my car back to its storage unit. Now that I've told my story here are my questions.

1. Is this just a water pump issue? If so who has rebuilt water pumps?

2. If its not a water pump issue could this be a cracked freeze plug or block?

I haven't had a chance to pull the radiator or the pump yet to get a closer look so its all speculative at this point. I just wanted to see if anyone has had a similar issue in the past before with this particular year. Thanks in advance for any help!

If the water is leaking from the weep holes at the bottom it needs a new pump.
If the coolant got too low it will overheat.
If the block is filled with rust it will find its way to the radiator core tubes and plug them up and it will overheat.
I would begine by replacing the water pump, flushing the block and radiator with hose pressure, fill with plain water and see what happens'
The most common problem it finding the above rust, having the radiator cleaned or replaced, removing the head, freeze plugs, etc. and cleaning out the block. The excessive rust is from having the water or anti-freeze in the system for many years.

Ther is a weep hole in the bottom of the pump. Water will come out there when the seal goes bad. Best way to check is to fill with water and put a couple pounds of pressure in the system and look for the leak.
The Filling Station may have a new pump.

Thanks I did that and when I do the fan sprays water droplets all over my engine compartment. Its a pretty steady leak when I top up the radiator. Just checked the vendor you mentioned and they don't seem to have the 39-40 style water pump. They seem almost impossible to find. Chevsofthe40s doesnt have them either.

I would first remove the old pump and make sure you have a 1940 engine. The 1940 and older pumps have one larger round hole on the back. The 1941 and up has two holes. Yo could/may have a later engine.

Its a 40 engine Ive confirmed the block number. Had a chance to get a 38 pump but the pulley is too big

Apart from the previous replies, all of which I agree with I am thinking if the car has been standing for some time the pump seal way well be a problem but a GOOD reverse flush through the radiator with compressed air assistance will not hurt considering you mentioned brown water.
Tony

I needed a waterpump for my 1938 Chevrolet. Instead of buying a new one, I found a shop in town that rebuilt mine for a little cheaper than a new one. Check the local shops in your area, I'm sure you'll find one that can do the job for you.

If your present pump is a Genuine Chevrolet (has GM on casting) you can remove the pulley and install it on a 1938 GM pump.

Here is a review of past posts to let you know you may have a much greater problem than a bad pump. Overheating issue.

Good luck, Mike

Thanks everyone. I know that when I last tried to fill her up the water that was running out was clear. I'm still going to flush the block and install the new pump and try again. I believe my overheating was mainly due to lack of fluid being retained by the system. It stayed around 160 before the water pump ruptured.

Btw is there a good solution that I can buy at an auto parts store to properly flush my radiator or water block? I know everyone said use pressure but aside from my garden hose I dont have much other than that

Prestone and other folks make products to flush your system. I think you are on the right track. There is a good chance that you may solve your problem with a new pump.